A wafer inspection apparatus includes, for example, a probe apparatus for performing electrical characteristics inspection of a wafer by using a plurality of devices, a burn-in inspection apparatus for performing an acceleration inspection of a wafer, and the like.
The probe apparatus generally includes a loader chamber for transferring a wafer and an inspection chamber for inspecting electrical characteristics of the wafer, in which the electrical characteristics of the wafer are inspected by controlling various devices within the loader chamber and the inspection chamber by a control device. The loader chamber includes a cassette loading unit for loading wafers by cassette, a wafer transfer mechanism for transferring a wafer between a cassette and the inspection chamber, and a pre-alignment mechanism for performing pre-alignment of the wafer while the wafer transfer mechanism transfers the wafer. The inspection chamber includes a temperature-adjustable loading table for loading the wafer thereon from the loader chamber and moving the wafer in X, Y, Z, and θ directions, a probe card disposed at an upper side of the loading table, and an alignment mechanism for performing alignment of a plurality of probes of the probe card and a plurality of electrode pads of the wafer in cooperation with the loading table. After the loading table and the alignment mechanism align the wafer and the probe card in cooperation, electrical characteristics of the wafer are inspected at a certain temperature as necessary.
When the wafer is heated and inspected at a high temperature, the heated wafer is thermally expanded. This results in a position deviation between the electrode pads of the heated wafer and the probes of the unheated probe card. Thus, the electrode pads and the probes cannot accurately come in contact, and the reliability cannot be secured. In the conventional art, before inspecting the wafer, the probe card is pre-heated to secure contact between the electrode pads and the probes.
On the other hand, in the case of a burn-in inspection apparatus, a plurality of electrode pads of a wafer retained and supported by a wafer tray and a plurality of bumps of a probe sheet are aligned and then the wafer tray, the wafer, the probe sheet, and the like are integrated through vacuum adsorption so as to be assembled as a sheet of a card. Next, the card is transferred to be mounted in a burn-in unit, and the wafer acceleration inspection is performed at a certain high temperature within the burn-in unit.
However, the conventional probe apparatus has the following problems. For example, in order to align the plurality of electrode pads of the wafer and the plurality of probes of the probe card by using a camera of the alignment mechanism while moving the loading table in the XY direction, there is need for a space for the movement of the loading table and a space for the movement of the camera of the alignment mechanism. Therefore, the inspection chamber itself, which is a major part of the probe apparatus, occupies a considerably large space in three dimensions. Further, the loader chamber requires a space for the transfer of the wafer from the cassette to the inspection chamber. Thus, where a plurality of probe apparatuses are installed depending on device production capabilities, the plurality of conventional probe apparatuses, which are arranged on plane, occupy a large installation space, resulting in high cost. Moreover, independently of the burn-in unit, the burn-in apparatus requires an independent wafer transfer mechanism or card-integration device in order to vacuum-adsorb and integrate the wafer, the probe sheet, and the like.
Further, in the case where a high temperature inspection is performed on the wafer, the wafer is heated up to a certain temperature (e.g., 150° C.). However, in order to restrain a position deviation between the electrode pads of the heated and thermally expanded wafer and the unheated probe card, the probe card is pre-heated to be thermally expanded by using the loading table. In this case, however, in order to prevent the probes of the probe card from being damaged, the loading table is moved to be very close to the probe card, and the probe card is pre-heated in a state that the wafer and the probes of the probe card are not in contact. This prolongs the time required for pre-heating the probe card. Furthermore, after the probe card is pre-heated, the thermally expanded wafer and the probe card should be aligned.